One of the mistakes some managers make, is that they don’t dare substitute their star players, even if it is crystal clear that their star player is under-performing. Case in point is the match Portugal – Chile June 28th 2017 (0-0) in the Confederation Cup 2017 where Sanchez had a very low football efficiency to start and where Sanchez had his football efficiency drop even further during the match. Nevertheless, Pizzi, the Chilean manager, substituted Vargas rather than Sanchez. Vargas’ his football efficiency was also dropping. Nevertheless, no matter how you look at it, Sanchez wasted more time and effort of his team mates and himself than Vargas.
If you look at all the matches Chile played in the Confederation Cup 2017, then you see how the football efficiency of both players declined during the match:
Nevertheless, clearly Vargas is the more efficient footballer here, wasting less time and energy of team mates and himself. The difference is less obvious if you only look at the one match against Portugal (with The Football Efficiency Monitoring System you can select which matches you want to look at in terms of football efficiency), but even then the difference is easy to see:
So it is a good decision to substitute either one of them for Rodriguez if you look at Rodriguez his football efficiency chart:
Yet, it is hard to see why Vargas would be substituted rather than Sanchez. Of course, there is an easy way to understand this substitution rather than Sanchez, namely that as a manager it is hard to substitute your star player. If you substitute your star player and you lose the match, the blame is on you. If your star player remains on the pitch and you lose, the blame is on him. Nevertheless, if your concern is for the team first over your own interest, then substituting the weakest link is the best option. The Football Efficiency Monitoring System helps the manager to justify such an action as the manager can show immediately after the match why he has substituted his star player.